This invention relates to a nozzle for discharging air from an air supply into an enclosed space, such as a room, or to a vehicle interior, having a control device for controlling deflection of air from the nozzle through a grill having a high degree of visual opacity to obscure elements behind the grill while maintaining a high face velocity and without significantly affecting or impairing deflection of the air stream as imparted thereto by the upstream intruder control member.
Current nozzle grills, as found in vehicles, for example, are very transparent visually in that large areas behind the grill can be seen at even large off-axis angles, up to 70 degrees. Many grills are thin perforated metal or plastic sheets which, while having relatively high visual opacity, cause a drop or loss in air stream face velocity. When the thickness (T) of the physical interstitial structure forming the grill is reduced, with a concurrent increase in the face velocity (e.g. reduction in losses), the visual opacity decreases and large areas behind the grill can be seen. When the physical thickness T of the interstitial material is made thin with vane-like depth L, the grill material interferes with the directionality imparted to the air stream by the upstream control device.
In Stouffer et al. U.S. Pat. No. 4,686,890 an air nozzle having an open frame plate intruder member is disclosed for controlling the directionality of air discharged from the nozzle. In Jackson U.S. Pat. No. 4,413,551, front plates and directionality control is achieved by relative lateral movements between the front and back plates and the only part of the grill which is visible is the front plate. A somewhat similar directionality control scheme is illustrated in Elfverson U.S. Pat. No. 4,928,582. In Gona et al. U.S. Pat. No. 3,672,293 commonly adjusted parallel vanes are used for directionality control.
An object of the present invention is to provide an improved air discharge nozzle, and, especially a discharge nozzle, particularly useful for vehicle interiors. A specific object of the invention is to provide an air discharge nozzle and method for vehicles having a grill which has a high degree of visual opacity to enhance design aesthetics, low impedance so that the face velocity remains high, and which does not significantly affect directionality of the air as imparted to the air stream by an upstream control mechanism and which, preferably, can be molded. Another specific object of the invention is to provide an improved directionality control mechanism.
According to the invention, the grill is comprised of a monolayer of polygonal cells in an array of cells, each cell being bounded by planar walls having a depth "L" interstitial thickness "T" and a diameter or major dimension "D", wherein the interstitial depth L is short enough such that the planar walls do not act as vanes to significantly affect directionality of the air as imparted by the upstream directionality control mechanism, the interstitial thickness T has a value such that the impedance to air flow is low and the ratio of T/D is such that there is low friction losses at the grill and the length to diameter ratio L/D is no greater than about 0.7 and no less than about 0.3, such that the relative visual opacity of the grill when viewed from any angle is high. In order to accommodate modern molding practices, in the preferred embodiment, the depth L is no greater than about 5 times the interstitial thickness T. In the preferred embodiment, the open cell area Ao must be at least about 76% of the available (total) area to obtain an acceptable 1800 ft/min face velocity at a blower pressure of 0.24 inches H.sub.2 O. As defined herein, visual opacity ranges from 0 percent for an open nozzle (e.g. no grill) to where the grill is in place 24 percent is obscured when the observer is looking directly on the cells and the observer's viewing angle changes from an axial alignment with the cells and becomes more and more visually opaque to where, in the case of the L/D ratio of 0.67 or a 56 degree viewing angle equals 100 percent opacity.
The upstream directionality control mechanism includes an open intruder frame having an upstream bounding edge joined to its downstream boundary edge by converging walls so that the cross-sectional area of the total shadow area of the frame projected on a plane normal to the axial center is essentially constant so that the impedance to air flow is essentially constant. A cross member joined to the frame member has an axially projecting control shaft which carries a spherical member frictionally received in a spherical socket formed in the grill such that the control shaft can easily be manually manipulated. When the end of the shaft projects beyond the grill in the form of a control knob, the knob points in the direction the air is caused to flow. Moreover, since the intruder is an open frame, the amount of angular movement of the control shaft is significantly reduced.